SU1264287A1 - D.c.electric drive - Google Patents

Abstract

The invention relates to electrical engineering and can be used to control two-zone electric motors (frequency control. Reliability is ensured by the fact that the control loop, ofipasoBaHHbm voltage regulator 16, valve converter 3 and voltage sensor 9, stabilizes the transmission coefficient of the gain channel with changes in the transmission coefficient of the converter 3, associated with a change in the network voltage, and also serves to partially dynamically compensate the delay In converter 3, in addition, the inverter mode overturns protection by comparing the input voltage of the non-linearity unit 13 and the signal from the output of the sensor I7 of the network voltage amplitude at the input of the network 14. When the ratio of the voltage amplitude of the network and the electromotive voltage of the electric motor is approached Since F is a dangerous limit at the output of the comparator block J.4, a positive signal appears, at the output of the non-scaffolding unit 18, a signal appears which, entering the restriction control input of block 5, causes a decrease in excitation current REPRESENTATIONS and ZDS motors. 2 3. p. F al. 5 il.

Description

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The invention relates to electrical engineering and can be used to control DC motors in electric drive circuits with two-zone speed control of the main drives of rolling mills, excavators and other responsible mechanisms.

The purpose of the invention is higher reliability and efficiency of the electric drive,

Fig. 1 shows a functional diagram of a direct current drive; figure 2 - diagram of the first adaptive filter; on fig.Z - the scheme of the second adaptive filter; Fig. 4 is a block diagram of an adjustable limit; FIG. 3 is an integrator circuit with an adjustable time constant.

The electric drive (Fig. 1) contains an electric motor 1, the excitation winding 2 of which is connected to a gate converter 3, to the control circuit of which the minimum excitation current setpoint generator 4, adjustable limit unit 5 and regulator 6 current regulator 6 are connected to its input 7 excitation current, sensors 8 and 9 of the current of the cortex and excitation voltage, adder 10, filters P and 12, non-linearity unit 13 with characteristic of the dead zone type with module extraction and comparison unit 14. The electric drive also contains a voltage sensor 15 on the electric motor core, an excitation voltage regulator 16, a network voltage amplitude sensor 17, a nonlinearity unit 18 with a dead zone type characteristic and a module allocation unit 19, the filter 11 being adaptive with filtering signals the high frequency filter 12 is adaptive with filtering low frequency signals, the excitation voltage controller 16 is connected between the excitation current controller 6 and the control input of the gate converter 3 and its second input is connected With the output of the excitation voltage sensor 9, the output of which, together with the output of the excitation current sensor 7, is connected to the inputs of the adder 10 connected to the adaptive filters 11 and 12, the control inputs of which are connected to the output of the excitation current sensor 7 11 is connected to the auxiliary input of the excitation current controller 7, the output of the adaptive filter 12, as well as the output of the nonlinearity unit 18, is connected to the limitation control input of the adjustable limiting unit 5, the second input of which is through the allocation unit 19 The module is connected to the sensor 8 current core, and

the input of the nonlinearity unit 18 through the comparison unit 14 is connected with the outputs of the voltage amplitude sensor 17 of the network voltage and the nonlinearity unit 13, the input of which is connected to the output of the core voltage sensor 15; Measuring motor 1 is connected to valve converter 20.

Adaptive filter 11 (figure 2) contains an integrator 21 with adjustable

constant time and serially connected amplifiers 22 and 23, the input of the first of which is the input of the filter, and the output of the second is its output, while the integrator 21 is on

to the feedback circuit of amplifiers 22 and 23, and its input of a change in time constant is connected via a nonlinearity block 24 to a control input of the filter.

 Adaptive filter 12 (FIG. 3) contains an aperiodic element with an adjustable time constant, made in the form of an operational amplifier 25, the input and output of which are

respectively, the input and output of the filter, and a resistor 26 is connected to the feedback circuit, the output of which, connected to the output of the amplifier 25, is connected to one of the outputs of the resistor 27,

the second terminal through capacitor 28 is connected to the input of amplifier 25 and to the drain of the field-effect transistor 29 with an insulated gate, the source of which is connected to the common bus, and the gate to the transceiver of the nonlinearity block 30, the input of which is the control input of the filter. At the input of the operational amplifier 25, a resistor 31 is turned on.

Claims (3)

The adjustable limiting block 5 (FIG. 4) contains a proportional amplifier 32, the inverting input of which is connected to the cathodes of diodes 33 and 34. The limiting input of the proportional amplifier 32 is connected to the output of the source 35 antiphase supporting voltages. The anodes of the diodes 33 and 34 are block inputs. The inputs of the anti-phase voltage source 35 are the limiting control inputs. The output of the proportional amplifier 32 is the output of the block. The integrator 21 with an adjustable time constant (Fig. 5) contains an operational amplifier 36, the input of which is connected to the first output of the resistor 37, the second output of which is the input of the integrator, and through a capacitor 38 to the first output of the resistor 39 and the drain of the field-effect transistor 40 insulated gate, which together form a voltage divider. The source of the field effect transistor 40 is connected to the common bus, and the gate to the input, which is the control input of the integrator. The second terminal of the second resistor 39 is connected to the output of the operational amplifier 36, which is also the output of the integrator. The drive works as follows. In the absence of voltage at the output of the converter 20 in the core circuit and after long standing, there is no current in the core of the electric motor I. Therefore, the voltage at the output (sensor 8 of the core current and the module allocation block 19 is absent, and the signal for controlling the limitation of the adjustable limitation block 5 is determined only by the signal from the output of the minimum excitation current setpoint 4. At the same time, the output of the adjustable limiting block 5 is the minimum signal that causes the minimum signals at the outputs of the exciter current regulator 6, the exciter voltage regulator 16 and the valve converter 3 in the excitation winding 2 circuit. The current in the winding 2 in The excitation of the j dpigatel is minimal, which causes the minimum heating of the winding 2. In this mode, the signals at the outputs of the sensor 7 of the excitation current and the sensor 9 of the excitation voltage are equal and at the output 50 de adder 10 the signal is zero, and therefore, the signals at the outputs of the first filter 11 and 12. When the voltage of the motor I is zero, the signals at the output of the sensor I5 of the voltage on the core and at the output of the third nonlinearity unit 13 are zero. The signal from the output of the nonlinearity unit 13 is compared to the block 14 in comparison with the signal from the output of the sensor 17 of the voltage amplitude of the AC mains, not equal to zero. As a result, the output of the comparison block 14 is negative, therefore, there is no signal at the output of the nonlinearity unit 18 . Thus, there are no signals at the inputs of the limit control. In this mode, the block 5 adjustable limits (figure 4) works as follows. In the absence of signals at the control inputs of the limitation, the signal at the output of the source of the antiphase voltage 35 is determined by the signal from the constant voltage source (in Fig. 4, the constant voltage source is not specified), is maximum and does not limit the signal to output of the proportional amplifier 32. As a result, the output of the adjustable limiting unit 5 produces a signal proportional to the signal for setting the minimum excitation current coming from the output of the setpoint 4, since the output signal of the unit 19 module extraction is absent. During acceleration of the motor I, the current at the output of converter 20 increases, a signal appears at the input of current sensor 8 and module extraction section 19. When the signal at the output of the module allocation unit 19 becomes larger than the signal at the output of setpoint A, the diode 33 in the circuit of the adjustable-limit unit 5 is turned off, and the diode 34 is unlocked and the output signal, the adjustable-limit unit 5 is determined by the signal at the output of the selection module 19 module. At the same time, the voltages at the output of the regulators 6 and 16 of the excitation current and the excitation voltage, and at the output of the converter 4 and the sensors 9 of the excitation voltage, begin to increase. Under the action of the voltage at the output of the converter 3, the current in the excitation winding 2 begins to increase. Since the current of the winding 2 due to its inductance increases more slowly than the voltage, the voltage at the output of the sensor 7 of the excitation current grows more slowly than at the output of the sensor 9 of the excitation voltage. Therefore, at the output of the adder 10 S, a signal appears, which is proportional to | k. „J4 and„ - (.- oCh) -: q uRpig), the voltage across the winding 2 of the bump; RQ is the resistance of the winding 2 in the cold state; ij is the current in excitation winding 2; L is the inductance of the dissipation winding 2 of excitation; Ng is the number of windings of the excitation winding; Рд - useful magnetic flux; otutgRg is the change in the resistance of the excitation winding 2 under the action of heat; v - temperature coefficient The adaptive filter 11, which is the real differentiating link, forms at the output a signal equal to L lk. w, i h dt dt, as the component, which is relatively slowly changing, becomes almost zero during differentiation. The signal from the output of the filter 11 is fed to the input of the regulator 6 of the drive current, as a result of which the excitation current control loop is dynamically stabilized. The differentiation is carried out by including in the direct channel two proportional amplifiers 22 and 23, and in a feedback channel - by integrator 21 with an adjustable time constant (Fig. 2). The regulation of the time constant, which is determined by the resistance of the resistor 37 and the capacitance of the capacitor 38 (FIG. 5), is carried out by changing the charging conditions of the capacitor 38. The changing of the charging conditions is done by changing the voltage at the output of the voltage divider consisting of a resistor 39 and a field-effect transistor 40, the gate of which receives a signal from the output of sensor 7 of the excitation current, processed using nonlinearity block 24. This change in the parameters of the charge circuit of the capacitor 38 leads to a change in the equivalent filter time constant in accordance with 876 changes in the electromagnetic time of the excitation winding. The result is a stabilization of the shape of the transient processes, which provides increased reliability. Adaptive filter 12 (FIG. 3) is an aperiodic link with adjustable constant time and serves to separate from the signal from the adder 10 a component proportional to Lg utgR V. The signal from the output of the filter 12 is fed to the input of limiting control of the adjustable limit block 5 and serves to limit the reference to the excitation current as a function of the heating of the excitation winding 2. This reduces the voltage at the output of the source 35 (Fig. 4) and, consequently, the voltage at the output of the adjustable limiting unit 5. As a result, the heating of the excitation winding 2 is limited and the reliability is increased. The time constant of the adaptive filter 12 is changed by changing the charging conditions of the capacitor 29, which is carried out by changing the voltage at the output of the voltage divider formed by the resistor 27 and the field-effect transistor 29. The nonlinearity unit 30 forms the law of change of the transition resistance of the drain - the source of the field-effect transistor 29 so that the cut-off frequency of the adaptive filter 12 is proportional to the change in the electromagnetic time constant of the excitation winding 2. The control loop, formed by the voltage regulator 16, the valve converter 3 and. a voltage sensor 9 provides stabilization of the gain of the forward channel of the gain with changes in the gain of converter 3 associated with changes in the network voltage, and also serves to partially compensate for the delay in converter 3. As a result, the stability of transients and; therefore, the reliability of the drive. In order to increase its reliability, the drive also provides protection against the inverting mode of the inverter 20 overturning when an inadmissible relationship between the EMF of the electric motor and the amplitude of the alternating voltage supplied to the network terminals of the converter 20 is raised. This protection is achieved by comparing the comparison of the voltage source with the output 14 block 13 of the nonlinearity and the signal from the output of the sensor 7 of the amplitude of the mains voltage a positive signal appears at the dangerous limit of the output of the comparator unit 14, a signal appears at the output of the nonlinearity unit 18, which, entering the limiting control input of the unit 5, causes a decrease in the excitation current and the electromotive voltage of the electric motor,. As a result of the application of the invention, the efficiency and reliability of the direct current drive is increased. Claim 1, A DC motor containing a motor whose excitation winding is connected to a gate converter, in the control circuit of which a series-connected mini-generator is connected. the maximum excitation current, the adjustable limiting unit and the excitation current controller with the exciter current sensor connected to its input, the core current and excitation voltage sensors, an adder, two filters, a nonlinearity unit with a dead zone-type characteristic with a modulus, and a comparison unit differing in that, in order to increase reliability and efficiency, a voltage sensor on the electric motor core, an excitation voltage regulator, an amplitude sensor of the network voltage, a second nonlinearity unit with a characteristic The second type of dead zone and the module allocation module, while the first filter is made adaptive with filtering high frequency signals, and the second is adaptive with filtering low frequency signals, the excitation voltage regulator is connected between the excitation current regulator and the control of the input of the hard converter and its the second input is connected to the output of the excitation voltage sensor, the output of which, together with the output of the excitation current sensor, is connected to the inputs of an adder, connected by its output to the inputs of both adaptive phi The control inputs of which are connected to the output of the excitation current sensor, the output of the first adaptive filter is connected to the auxiliary input, the excitation current controller, the output of the second adaptive filter, as well as the output of the second nonlinearity block, to the control input of the adjustable limitation block, the second input through which the module is connected to the current sensor core, the input of the second nonlinearity unit is connected to the outputs of the network voltage amplitude sensor and the first nonlinearity block through the comparison unit Spine, the input of which is connected to the output of the voltage sensor on the crust. 2. The drive according to claim 1, wherein the first adaptive filter comprises an integrator with an adjustable time constant and two serially connected proportional amplifiers, the input of the first of which is the input of the filter, and the output of the second is its output, the integrator is connected to the feedback circuit of the amplifiers, and its input of the change in time constant is connected to the control input of the filter via a nonlinearity unit. 3. Electric drive according to PP, 1 and 2, which is based on the fact that the second adaptive filter contains an aperiodic link with an adjustable time constant, made in the form of an operational amplifier, the input and output of which are respectively the input and output of the filter, and the reverse circuit connection, a resistor is connected, the output of which is connected to the output of the amplifier and connected to one of the terminals of the second resistor, the second output of which through a capacitor is connected to the input of the amplifier and to the drain of an isolated-gate field-effect transistor li ne to a common bus, and the gate - to the output of the nonlinear unit, whose input is a control input of the filter. . 7 / a (puf.i (Paul R